Using the Finite-difference methods (FDM) to estimate the value of Bermudan Swaption. Here, we assume that the floating rate at each time point conforms to Hull-White model.
In Bermudan swaption, the owner is allowed to enter the swap on several pre-specified dates, usually coupon dates of the underlying swap. Notice that we evaluate the value of the swaption as a payer who pay the fixed leg and receive the floating leg of the interest rates.